/*
* Copyright (c) 2006-2007 Erin Catto http:
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* Converted for The Render Engine v2.0
* Aug. 4, 2010 Brett Fattori
*/

Engine.include("/physics/common/math/b2Vec2.js");

Engine.initObject("b2Mat22", null, function() {
   
   var b2Mat22 = Base.extend({

      col1: null,
      col2: null,
      
      constructor: function(angle, c1, c2) {
         if (angle==null) angle = 0;
         // initialize instance variables for references
         this.col1 = new b2Vec2();
         this.col2 = new b2Vec2();
         //

         if (c1!=null && c2!=null){
            this.col1.SetV(c1);
            this.col2.SetV(c2);
         }
         else{
            var c = Math.cos(angle);
            var s = Math.sin(angle);
            this.col1.x = c; this.col2.x = -s;
            this.col1.y = s; this.col2.y = c;
         }
      },

      Set: function(angle) {
         var c = Math.cos(angle);
         var s = Math.sin(angle);
         this.col1.x = c; this.col2.x = -s;
         this.col1.y = s; this.col2.y = c;
      },

      SetVV: function(c1, c2) {
         this.col1.SetV(c1);
         this.col2.SetV(c2);
      },

      Copy: function() {
         return new b2Mat22(0, this.col1, this.col2);
      },

      SetM: function(m) {
         this.col1.SetV(m.col1);
         this.col2.SetV(m.col2);
      },

      AddM: function(m) {
         this.col1.x += m.col1.x;
         this.col1.y += m.col1.y;
         this.col2.x += m.col2.x;
         this.col2.y += m.col2.y;
      },

      SetIdentity: function() {
         this.col1.x = 1.0; this.col2.x = 0.0;
         this.col1.y = 0.0; this.col2.y = 1.0;
      },

      SetZero: function() {
         this.col1.x = 0.0; this.col2.x = 0.0;
         this.col1.y = 0.0; this.col2.y = 0.0;
      },

      Invert: function(out) {
         var a = this.col1.x;
         var b = this.col2.x;
         var c = this.col1.y;
         var d = this.col2.y;
         //var B = new b2Mat22();
         var det = a * d - b * c;
         //b2Settings.b2Assert(det != 0.0);
         det = 1.0 / det;
         out.col1.x =  det * d;  out.col2.x = -det * b;
         out.col1.y = -det * c;  out.col2.y =  det * a;
         return out;
      },

      // this.Solve A * x = b
      Solve: function(out, bX, bY) {
         //float32 a11 = this.col1.x, a12 = this.col2.x, a21 = this.col1.y, a22 = this.col2.y;
         var a11 = this.col1.x;
         var a12 = this.col2.x;
         var a21 = this.col1.y;
         var a22 = this.col2.y;
         //float32 det = a11 * a22 - a12 * a21;
         var det = a11 * a22 - a12 * a21;
         //b2Settings.b2Assert(det != 0.0);
         det = 1.0 / det;
         out.x = det * (a22 * bX - a12 * bY);
         out.y = det * (a11 * bY - a21 * bX);

         return out;
      },

      Abs: function() {
         this.col1.Abs();
         this.col2.Abs();
      }
      
   });
   
   return b2Mat22;
   
});
